module: better OOPS and lockdep coverage for loading modules

If we put the module in the linked list *before* calling into to, we
get the module name and functions in the OOPS (is_module_address can
find the module).  It also helps lockdep in a similar way.

Acked-and-tested-by: Joern Engel <joern@lazybastard.org>
Tested-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>